Introduction to coronavirus
Coronaviruses (CoVs) are enveloped positive-sense RNA viruses characterized by club-like spikes that project from their surface and have an unusually large RNA genome with unique replication strategy. They cause a variety of diseases in mammals and birds, ranging from enteritis in cows and pigs and upper respiratory disease in chickens to potentially lethal human respiratory infections.1-3
The past twenty years has seen several viral epidemics, such as the severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002–2003, influenza A (H1N1) in 2009, and Middle East respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia in 2012.1-3
In the timeline that reaches the present day, novel coronavirus disease (COVID-19 [SARS-CoV2]), a novel virus belonging to the family Coronavirus (CoV), is causing a global pandemic. An epidemic of cases with unexplained lower respiratory infections was first detected in early December 2019 in Wuhan, the largest metropolitan area in China's Hubei province.1-3
Coronaviruses are the largest group of viruses belonging to the Nidovirales order, which is further classified as seen in Figure 1.3,4,5 Figure 1: Classification of coronavirus
Pathogenesis and immune response
Figure 2. Lifecycle of coronavirus
CoV binds ACE 2 (type 1 transmembrane metallocarboxypeptidase with homology to angiotensin- converting enzyme [ACE]) cell surface receptors of epithelial cells in the respiratory tract through its spike proteins, as depicted in Figure 2 above. CoV-receptor binding mediates proteolytic cleavage followed by fusion with the host cell membrane, and viral RNA is released into the host cytoplasm, where viral nucleoproteins uncoat. Viral RNA is translated to produce unglycosylated proteins, which are then trafficked through Golgi body to undergo glycosylation. Viral capsids assemble from viral RNA and nucleocapsid proteins in the cytoplasm. Vesicles fuse with the cell membrane and release CoV virions externally.4
Want to read more?
Log in or sign up to access all Neurodiem content.
Already have an account? Log In
Dr. Beladakere Ramaswamy has nothing to disclose.